The technology of using microwave energy for heating an object to a higher temperature has been used for many years. It is especially popular in the food service industry where microwave ovens are widely used. Most microwave ovens are designed with a heating chamber of a rectangular shape and a large volume. The microwave energy is dispersed inside the heating chamber and therefore is not available in a concentrated form. As a result, the time required for heating an object, even though shorter than a conventional convection oven, is still quite appreciable. For instance, most food items, even of a small size, require a heating time of between two to five minutes. The lengthy heating time prohibits the use of microwave ovens in vending machines.
In a typical fast food vending machine, after a consumer deposits money into the machine and makes a selection, the selected item is immediately delivered to a discharge chute to the consumer. If a conventional microwave oven is used in such a machine, the heating time required even for a small food item would not be acceptable. A general survey indicates that a consumer demands that a food item to be heated and delivered to him in a very short period of time, i.e., less than 30 seconds.
It is therefore an object of the present invention to provide a microwave heating chamber for use in a vending machine that does not have the drawback of conventional microwave heating chambers which require long heating time.
It is another object of the present invention to provide a microwave heating chamber for use in a vending machine that is in a cylindrical shape to enable the formation of a maximum microwave energy zone inside the chamber.
It is a further object of the present invention to provide a cylindrically shaped microwave heating chamber for use in a vending machine capable of holding a food item at a predetermined position inside the chamber for exposure to maximum microwave energy.
It is another further object of the present invention to provide a cylindrically shaped microwave heating chamber for use in a vending machine equipped with an object holding plate such that an object may be heated in a short period of time.
It is still another object of the present invention to provide a cylindrically shaped microwave heating chamber for use in a vending machine equipped with an object holding plate such that an object may be heated to a desirable temperature in a time period of less than 30 seconds.